Vulkan: Wrap barrier data into PipelineBarrier class This is preparation CL without introducing any functional change. This Cl wraps barrier data into its own class and put necessary data structures in place. It still uses one vkCmdPipelineBarrier call. Bug: b/155341891 Change-Id: If9c70d24873bd9b89e598acfba2eeee364f0b6c1 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2185149 Commit-Queue: Charlie Lao <cclao@google.com> Reviewed-by: Jamie Madill <jmadill@chromium.org>